1. Field of the Invention
The present invention relates to an electro-conductive member for electrophotography for use in an image-forming apparatus that adopts an electrophotographic process, a process cartridge, and an electrophotographic apparatus.
2. Description of the Related Art
Japanese Patent Application Laid-Open No. 2006-189894 describes that an electro-conductive material obtained by adding a quaternary ammonium salt as an ionic electro-conductive agent to a polymer component such as a urethane rubber has been used as a material for forming a charging roller that charges a photosensitive drum of an electrophotographic apparatus. In addition, Japanese Patent Application Laid-Open No. 2006-189894 discloses that the above-mentioned ionic electro-conductive agent has a limited ability to reduce the electrical resistance of the charging roller, and that the electrical resistance of the charging roller formed of the above-mentioned electro-conductive material increases to a large extent when electricity is passed through the charging roller, and hence a trouble occurs in charging over time. In addition, Japanese Patent Application Laid-Open No. 2006-189894 discloses that the above-mentioned problems can be solved by using a quaternary ammonium salt having a specific structure as the ionic electro-conductive agent.